1. Field of the Invention
This invention relates in general to certain new and useful improvements in a moldboard plow apparatus, and more particularly, to a moldboard plow apparatus which is capable of simultaneously inverting a pair of opposite soil sections and throwing an depositing the soil sections in an inverted condition and in furrows from which the other of the soil sections were removed.
2. Brief Description of the Prior Art
In the growing of most plant products, plowing is a necessary and integral operation. The reasons for the plowing and the seasonal times in which plowing is conducted may vary from one farming operation to another. However, one of the principal reasons for plowing is to bury ground stubble and/or undesirable plants after a crop has been harvested and to insure that no undesirable growth, such as weed growth is still present on the surface, so that the surface may be prepared for the planting of a new crop.
Moldboard plows have been used for centuries in various forms. A few of the early moldboard plows are described in U.S. Pat. No. 1,320 to Barnaby and in U.S. Pat. No. 114,044 to L. P. Rider. The conventional moldboard plow, as used in early times and as presently used, shears a strip of soil from the ground and then inverts it by rolling it over in a manner somewhat similar to the turning of a page in a book. The moldboards also cause a displacement of the removed strip of soil by a distance approximately equal to one furrow width. In this type of plowing operation, fresh soil is exposed on the upper surface of the inverted strip of soil and weeds and stubble are buried under the deposited strip of soil.
This type of soil movement necessarily causes the first strip of soil to be deposited on previously unplowed soil and also causes the opening of a furrow or channel in the ground surface. In farm terminology, this operation is described as the first strip of soil "being thrown onto the land". The second and subsequent plowed strips of soil are also thrown into the open furrows made by the previous plows. As a simple example, if a strip of soil is removed, it may be thrown into the furrow to its immediate left. The next strip of soil is then also thrown into the furrow to its left and so forth. Thus, it can be observed that during the plowing operation, the plowed soil surface is moved one furrow width in the same direction of throw each time a soil strip is turned over. Moreover, when the plowing operation has been completed, the last furrow (an open furrow) is left unfilled and in addition, one soil strip, (the first plowed strip) is left deposited on the unplowed land leaving a ridge.
In accordance with the above identified plowing arrangement, it can be seen that if plowing began and ended at the same place each time the field was plowed, the plowed upper surface would be moved in a single direction and eventually, a hill would build up at the starting strip and a trench would develop at the ending furrow.
In essentially all commercially available moldboard plows, the construction is such that the soil strip is turned over in one direction only. In other words, essentially all of the present commercially available moldboard plows form furrows and move the soil either to the right or to the left, but always in that same direction. Accordingly, when plowing a large field, it is necessary to divide the field into an acceptable series of geometric shapes for plowing so that time consuming long runs at the end of the field are minimized. In accordance with this type of plowing operation, one geometric shape of land is plowed, the next geometric shape is then subsequently plowed and so forth.
Multiple plows may be mounted on a single frame which make it possible to limit the number of traverses across a particular field. However, this construction does not solve the problem of throwing the soil strips removed from the land in only one direction. Accordingly, there is still lost time in the plowing operation.
The construction of mounting a large number of plows on a frame necessarily causes a staggering of the positioning of the plows on the frame. This increases the overall length of the plow assembly. As a result, turning around at the end of each row requires much more space. As a further result, less land is available for the growing of crops
Inasmuch as the commercially available moldboard plows only throw soil in one direction, the plow has a resultant large reaction force which tends to force the plowshares laterally away from the direction of throw. This inherently creates a large amount of frictional force which tends to resist the movement of the plowshares. The friction generated by this force can result in as much as 50 percent of the total pulling force required for the moving of the plowshares. See for example, Richey, C.B., et al., Agricultural Engineers Handbook, McGraw-Hill Book Co., Inc., New York, 1961, pp. 130-131.
In an attempt to decrease the large frictional forces generated, a so-called "landslide", which is customarily a piece of metal strip, is mounted on the frame of the plow and slides along the inside of a wall of the opened furrow. Some moldboard plow apparatus have been equipped with rollers in order to decrease the frictional forces which are generated. However, because of other difficulties which may arise, the rollers are less desirable than the use of the landslide. In either case, the rollers or the landslide add additional weight to and also increases the cost of construction of the moldboard plow.
In order to overcome some of the problems in the presently available multiple plow constructions, there has been the introduction of the so-called "roll-over" multiple plow. This type of plow apparatus includes two sets of plows which are mounted to a rotating beam or shaft on the frame of the plow apparatus. The plows on each of the two sets have opposite throws, that is they direct the soil strips in opposite directions. The plows are mounted on the shaft 180 degrees apart with one set disposed in an upside down condition while the other set is plowing. In accordance with this construction, one set of plows is used to plow in one direction across the field. At the end of the plowing of a strip, the plows are lifted from the ground and the shaft retaining the plows is rotated 180 degrees about its axis such that the plowing apparatus is turned around for the return trip across the field. The opposite set of plows are lowered into the soil for forming a furrow therein, and plowing is continued with the soil strips still being thrown in the same direction relative to the ground's surface.
In accordance with the above identified plowing operations performed with roll-over flows, they are necessarily required to have twice as many moldboards mounted on the frame as the number of furrows to be plowed. This construction results in a great increase in weight, not only because of the number of moldboards, but because of the massive framework required to support the roll-over mechanism. Accordingly, the roll-over plow retains the undesirable characteristics of high land side friction, excessive length and unidirectional soil movement.
There has been a need for a moldboard plow which is capable of minimizing the frictional losses which are inherent in most of the presently available moldboard plow constructions. In addition, there has been a need for a moldboard plow which can minimize the frictional losses without excessive length and without the redundancy of moldboards to perform the plowing operation. Such a plow construction must not be massive with a substantial amount of excess weight for each plow, or otherwise a greater amount of power is required for moving of the plow apparatus. Finally, there has been a need for a moldboard plow apparatus which does not throw and leave a soil strip on the land and which does not leave an open furrow.